Computer-implemented method of monitoring the performance of a reverse osmosis membrane in a drinking water supply system

ABSTRACT

A water treatment system is provided having an encapsulate manifold with a reverse osmosis cartridge and one or more filter cartridges. The filter cartridge includes a detent for being received within a slot in the manifold head for secure locking engagement. The water treatment system further includes a single probe conductivity monitoring system for monitoring the performance of a reverse osmosis membrane. The water treatment system is also provided in a modular arrangement wherein manifold heads are physically and fluidly coupled together via a clip which interfaces with the modular manifold heads. The water treatment system also allows for a retrofit application to include a permeate pump. The cartridges are also designed to provide a minimum annular inlet gap to minimize spillage during changing of the cartridges.

This application is a divisional application of U.S. patent applicationSer. No. 11/814,808, filed on Sep. 24, 2007, now U.S. Pat. No.7,736,503, and which claims priority to International Application No.PCT/US06/03172 filed Jan. 27, 2006, claiming benefit to U.S. ProvisionalPatent Application Ser. No. 60/647,680, filed Jan. 27, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to water treatment systems and, inparticular, to such systems having an encapsulated manifold head and areverse osmosis cartridge and one or more filter cartridges.

2. Description of Related Art

Reverse osmosis systems are known. The main part of the system is asemi-permeable membrane through which the untreated water passes. Suchsystems typically include an additional carbon or ceramic filter whichremoves contaminates either prior to passing through the membrane orafter. Such systems are often installed in residential applications.

The prior art includes electronic systems which detect when the reverseosmosis membrane requires replacement. Typical prior art systems includemeasuring the conductivity of the water entering the reverse osmosiscartridge, and then measuring the conductivity of the water at theoutlet of the reverse osmosis cartridge. The conductivity of the wateris proportional to the total dissolved solids. A ratio of theconductivity levels will provide an indication of the rejectionefficiency of the reverse osmosis membrane.

Prior art systems also include an application wherein a permeate pump isincluded in a factory installation. The permeate pump provides greaterefficiency in the system. The permeate pump increases the net pressureacross the reverse osmosis membrane by isolating the membrane pressurefrom the pressure in the products water and thus reducing the permeateback pressure.

The prior art also includes systems which address reducing the spillageof fluid occurring during replacement of the cartridges.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved lockingmechanism for a filter cartridge and manifold head.

It is a further object of the present invention to provide an improvedmethod of monitoring the performance of a reverse osmosis membrane in adrinking water supply system.

It is a further object of the present invention to provide a modularmanifold head system.

It is an object of the present invention to provide a system forretrofitting a reverse osmosis filter system to include a permeate pumpapplication.

It is an object of the present invention to provide a cartridge whichhas a reduced inlet opening to reduce spillage during changing of thecartridge.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a water treatment system with a reverseosmosis cartridge and two filter cartridges.

FIG. 2 is a perspective view of a filter cartridge of FIG. 1.

FIG. 3 is a top view of the filter cartridge of FIG. 2.

FIG. 4 is an exploded view of the filter cartridge of FIG. 2.

FIG. 5 is a bottom perspective view of a manifold head incorporated inthe water treatment system of FIG. 1.

FIG. 6 is a block diagram of a reverse osmosis membrane monitoringsystem.

FIG. 7 is a process flow chart for the system of FIG. 6.

FIG. 8 is a perspective view of a modular manifold head system.

FIG. 9 is a top perspective view of a modular manifold head.

FIG. 10 is a schematic diagram of a reverse osmosis water treatmentsystem with a permeate pump.

FIG. 11 is a cross-sectional view of the modular manifold head andcartridges of FIG. 1.

FIG. 12 is a top perspective view of a modular manifold head in apermeate pump application.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

FIG. 1 shows one embodiment of a water treatment system 10 in accordancewith the present invention. The system includes a manifold head 12, (seeFIG. 5) a first filter cartridge 14, a reverse osmosis cartridge 16 anda second filter cartridge 14. A manifold cover 20 is also shown.

FIG. 2 shows a filter cartridge 14 in accordance with the presentinvention. The filter cartridge 14 includes a housing 22 having acartridge outer annular collar 24 with a double lead thread 26. Acartridge inner annular collar 28 is also shown which includes an O ringto provide a seal. A connection fitting 32 is shown extending throughthe cartridge inner annular collar 28.

FIG. 3 shows a top view of the filter cartridge 14 and shows thecylindrical wall 34 of the cartridge inner annular collar 28, as well asthe longitudinal extending bead 36.

FIG. 4 shows the filter cartridge 14 in an exploded view so as to moreclearly show the longitudinal extending bead 36. It can be seen that thelongitudinal extending bead includes a leading end 38.

FIG. 5 shows the manifold head 12 having the filter cartridge connectionfitting 40. The filter cartridge connection fitting 40 includes athreaded outer annular collar 42 and an inner annular collar 44. Theinner annular collar 44 having an annular lip 46 and four longitudinalslots 48. The longitudinal slots 48 are equally spaced apart from oneanother.

It will be appreciated that when the filter cartridge 14 is rotated intoa fully secured position onto the connection fitting 40, the filtercartridge 14 comes to rest with the longitudinal extending beads 36being received by the respective slot 48.

FIG. 6 shows a block diagram of a system for monitoring the performanceof a reverse osmosis membrane. The system includes a microcontrollerhaving a memory wherein a program resides. The system includes a singleprobe set which is located downstream of the reverse osmosis membrane.The probe set includes a reference resistor and a thermal resistor. Themicrocontroller is coupled to a faucet LED for providing an indicationto replace the reverse osmosis cartridge. The microcontroller is alsocoupled to an onboard LED for feedback during operation of an onboardpush button also coupled to the microcontroller. A water flow sensor isalso coupled to the microcontroller.

FIG. 7 shows a block diagram which represents the functional steps asexecuted by the program resident in the memory.

FIG. 8 is an embodiment of a modular water treatment system. The watertreatment system shown in FIG. 8 includes a modular manifold head 96, amanifold cover, a first filter cartridge, a reverse osmosis cartridgeand a second filter cartridge. Also shown is a further modular manifoldhead 104 and cover, as wells as additional cartridge units. The systemof FIG. 8 provides a modular system wherein additional modular manifoldunits may be coupled to the water treatment system via a clip 110. Theclip includes a plurality of arms 112 extending from a planar bodyportion 114. Each arm 112 includes a slot 116 and a slanted leading edge118. The clip 110 also includes a tubular portion 120 extending throughthe main body portion. The tubular portion 120 includes a bore 121extending throughout the tubular portion.

Each manifold includes an end wall 98 having four openings 100.

FIG. 9 shows a perspective view of the manifold including the two endseach having four openings 100. The openings are arranged in pairs, oneabove the other. For example, lower opening and upper opening compriseone pair. Each pair of openings includes a pair of upright walls in aspaced apart facing relationship. The upright walls are shown extendingfrom the interior surface of the end wall and the lower surface of themanifold head. A flange 136 extends from the inner surface of the endwall towards the interior compartment of the manifold head. The flange136 includes an upper ramp and a lower ramp 138, 140. The flange 136includes a forward edge 142 and first and second side edges 144, 146.The forward edge is generally parallel to the end wall. The first sideedge and second side edges form the upper ramp and lower ramp. The upperramp and lower ramp diverge from one another in a direction away fromthe inner interior surface towards the interior compartment of themanifold head. One of the four flanges 136 is shown in phantom in FIG.9. The ramps include a proximal end and a distal end. The proximal endis located slightly away from the edge of the opening. The distal end isspaced in an interference relationship regarding alignment of theopening. FIG. 9 A shows additional detail.

With reference to FIG. 8, it will be appreciated that as the clip 110 isinserted into the openings of the manifold head to the right of thefigure, the slanted edge of each of the resilient arms 112 will bedeflected by the respective ramp. Once the clip 110 is fully insertedthrough the four openings 100, the slot will extend past the distal endand the two arm pairs will clamp about the respective distal end withthe edge of the slot coming into locking engagement with the distal endof the ramp. Meanwhile, the tubular portion 120 will be received by thetube fitting connector for sealing engagement. The other modularmanifold head will be coupled in similar manner.

FIG. 10 shows a graphical representation of a water treatment systemwherein an automatic shut-off valve cover may be removed and replacedwith another cover adapted to accommodate a permeate pump application.With reference to FIG. 11, a cross-section of a water treatment systemis shown including the modular manifold head, first cartridge, reverseosmosis cartridge and second filter cartridge. The manifold head isshown to include a connection fitting for receiving the respectiveconnection fitting of the reverse osmosis cartridge. The manifold headincludes a first manifold access port for coupling to an output of areverse osmosis cartridge, a second manifold access port coupled to anoutput of a reverse osmosis stage. A non-permeate pump cover is adaptedto seal the first and second access ports for a non-permeate pumpapplication. A permeate pump cover is adapted to also seal the first andsecond access ports and includes a permeate pump output port whichreceives a tube fitting connector. The permeate pump cover includes afirst access and a second access port and a flow channel incommunication with the first and second access ports, as well as thepermeate pump output port. A check valve assembly is located in thefirst access port for coupling the output of the reverse osmosiscartridge. The second cover includes a substantially planer body portionwhich defines a first end and a second end. Mounting holes are providedfor fastening the cover to the manifold head.

The manifold includes a lower diaphragm receptacle portion having anopened upper portion. The second cover includes an upper diaphragmreceptacle portion for mating with the opened upper portion to form adiaphragm cavity which receives a diaphragm. The upper diaphragmreceptacle portion includes an opening and fluid communication with thefluid channel. The manifold head includes a flow channel coupled to anoutput port of a pre-filter stage and an input port of the reverseosmosis stage, wherein the flow channel is in fluid communication withthe lower diaphragm receptacle portion of the manifold head. It will beappreciated that the water treatment system may be assembled at thefactory with a non-permeate pump cover, wherein the plug is provided atthe permeate pump output port. A retrofit kit may be provided whereinthe first cover is removed and replaced with the second cover having thetube fitting connector. A quarter inch tubing may then be coupled to thetube fitting connector and extend through a routing hole as shown inFIG. 12. The tubing extends downward and to a permeate pump as shown inFIG. 10. The permeate pump has a permeate outport having a tubing whichruns to a T-connector. The T-connector has a further tubing coupled to astorage tank, as well as tubing coupled back to the manifold head. Thebrine side of the permeate pump includes a brine end from the drain flowof the manifold head and a brine out tubing which couples to the drainpoint. For sake of completeness, the tubing is also shown coming fromthe supply inlet and tubing is shown going to the faucet.

The installation kit includes at a minimum the second cover and furthermay include a replacement check valve, as well as replacement O rings,tubing, fasteners and installation instructions.

FIG. 11 also shows the filter cartridge having a reduced gap at theconnection fitting in order to minimize spillage during changing of thefilter cartridge. The novel features of the filter cartridge areexplained below. However, it will be apparent that the features can beincorporated into the reverse osmosis cartridge as well.

The filter cartridge includes external cartridge housing having acylindrical portion with a top portion and a bottom portion. The bottomportion has a closed end. The top portion includes a shoulder having agenerally cylindrical neck portion extending upward from the shoulder.The cylindrical neck portion defines a portion of a connection fitting.The cylindrical neck portion defines a cylindrical bore having acylindrical bore wall which defines a first diameter. The cylindricalbore wall includes an annular ring protruding from the wall and defininga second diameter which is smaller than the first diameter. An internalcartridge housing includes a top portion with a shoulder, a tube portionextending upward from the internal shoulder, and the tube portiondefining an outlet bore. The tube portion defines an outer diameterhaving a third diameter, wherein the third diameter is smaller than thefirst and second diameter. The tube portion and the annular ring definea cartridge inlet having an annular gap. It will be appreciated that theannular gap is minimized by this design and thereby reduces thelikelihood of spillage. The manifold head is adapted to conform with thefilter cartridge. In particular, the manifold head includes a connectionfitting which includes an internal annular collar having a lengthdefined such that when the cartridge is assembled to the manifold, theinternal annular collar extends around the tube portion and up to theannular ring, with a minimum spacing for tolerance.

While the present invention has been particularly described, inconjunction with a specific preferred embodiment, it is evident thatmany alternatives, modifications and variations will be apparent tothose skilled in the art in light of the foregoing description. It istherefore contemplated that the appended claims will embrace any suchalternatives, modifications and variations as falling within the truescope and spirit of the present invention.

1. A computer-implemented method of monitoring the performance of areverse osmosis membrane in a drinking water supply system, the methodcarried out by a computer program, the method comprising the steps of:determining the flow of a predetermined amount of water through thesystem; measuring the initial water conductivity downstream of thereverse osmosis membrane; calculating, using the measured initial waterconductivity, a threshold trip point which corresponds to apredetermined total dissolved solids rejection ratio, whereincalculating said threshold trip point includes: measuring said initialproduct water conductivity values; equating an average of said initialproduct water conductivity values to said total dissolved solidsrejection ratio; and calculating said threshold trip point as apercentage of said average; storing the threshold trip point in memoryof the system; routinely measuring the water conductivity downstream ofthe reverse osmosis membrane; determining whether the waterconductivity, as routinely measured in the prior step, is below thethreshold trip point; and providing an indication upon determining whenthe water conductivity is below the threshold trip point.
 2. The methodof claim 1, wherein the step of initiating includes a power on routine.3. The method of claim 1, wherein the step of initiating occurs afterthe reverse osmosis membrane has been replaced.
 4. The method of claim3, wherein the step of initiating includes sending an initiaterecalibration signal to a microcontroller of the system.
 5. The methodof claim 1, wherein the step of initiating includes a user activatedswitch to signal a reverse osmosis membrane change and to initiate arecalibration.
 6. The method of claim 1, wherein the predeterminedamount of water is in a range of 10-30 gallons.
 7. The method of claim1, wherein the predetermined amount of water is 15 gallons.
 8. Themethod of claim 1, wherein the step of measuring the water conductivityincludes the step of averaging a range of 10-50 measurements.
 9. Themethod of claim 1, wherein the step of measuring the water conductivityincludes the step of averaging 20 measurements.
 10. The method of claim1, wherein the step of measuring the initial water conductivitydownstream of the reverse osmosis membrane and the step of routinelymeasuring the water conductivity includes measuring product water. 11.The method of claim 1, wherein the step of calculating includesassociating the initial measured water conductivity with an assumedpercentage rejection of total dissolved solids.
 12. The method of claim11, wherein the total dissolved solids rejection ratio is in a range of80-100%.
 13. The method of claim 11, wherein the total dissolved solidsrejection ratio is 90%.
 14. The method of claim 1, wherein the thresholdtrip point corresponds to a predetermined total dissolved solidsrejection ratio in the range of 60-80%.
 15. The method of claim 1,wherein the threshold trip point corresponds to a predetermined totaldissolved solids rejection ratio of 75%.
 16. The method of claim 1,wherein the step of providing an indication includes illuminating alight emitting diode.
 17. The method of claim 1, wherein the memory is anonvolatile memory.